The proposed research seeks to uncover details of tRNA solution structure and dynamics by new proton nmr methods. Resolved resonances for certain carbon-bound aromatic protons have been discovered and the spectrum shown to be consistent with the crystal structure in its present state of refinement. These resonances of several tRNA's will be pursued for their utility in probing structure and motion in single strand, double helix and tertiary bond regions. Selective relaxation effects due to paramagnetic metal ions are found in the aromatic region and will be used to pinpoint divalent cation binding sites. Relaxation time measurements will be used to determine aspects of structure in partially unfolded tRNA. Modified base resonances will be utilized for several E. coli tRNA's not previously examined by this method.